1. Field of the Invention
This invention relates to a liquid phase degreasing method, a system and apparatus, and solvent therefor.
2. Description of the Prior Art
A variety of contaminates in the form of lubricants, including petroleum products, water soluble oils and synthetic or semisynthetic fluids, are employed in metal working and in the repair of metallic objects such as automobile parts. Some of these fluids pose difficult problems for removal of these contaminants from the surface of the objects. Many of these problems are associated with environmental concerns both from an atmospheric pollution and waste disposal standpoint.
The prior art solutions to these cleaning problems have been directed to vapor degreasers using chlorinated solvents such as 1, 1, 1-trichloroethane, trichloroethylene, perchloroethylene or methylene chloride. The term "degreaser" is a term of art for removing all manner of contaminants from solid surfaces such as oil, grease, welding flux, water surfactants, metal salts and the like.
However, the prior art vapor degreasers pose significant environmental problems. The chlorinated solvents frequently break down and form corrosive hydrochloric acid in the presence of water. The vapor phase operation requires the use of expensive vapor recovery systems without which there would be significant atmospheric pollution. For example, U.S. Pat. No. 3,460,990 to Barday illustrates the complicated means needed in a closed system to perform the steps of a vapor degreasing method.
It is thus apparent that a need exists for a degreasing method and system which minimizes the dangers of waste disposal and atmospheric pollution in a simple cost effective manner. However, the prior art, when considered as a whole, neither taught nor suggested to those of ordinary skill in this art at the time the present invention was made how such need could be fulfilled.